<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title></title>
</head>
<body>
  <a href="https://cn.bing.com/">打开url</a>
  <button id="urlBtn">打开url</button>
  <button id="folderBtn">打开目录</button>
  <iframe id="iframe" width="100%" height="500" src="https://cn.bing.com/" frameborder="0"></iframe>
  <script src="./index.js"></script>
</body>
</html>